Multi-color liquid crystal display

ABSTRACT

A display and methods of driving the display, where the display includes a plurality of pixels, where some colors are present in every pixel, and some colors are only present in less than all of the pixels.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. patent applicationSer. No. 11/009,515, filed Dec. 13, 2004 and entitled Multi-PrimaryLiquid Crystal Display, which claims the benefit of U.S. ProvisionalPatent Application, 60/529,101, filed Dec. 15, 2003 and the benefit ofU.S. Provisional Patent Application, 60/604,461, filed Aug. 26, 2004,the disclosures of all of which are incorporated herein by reference intheir entirety.

FIELD OF THE INVENTION

The invention relates generally to multi-primary color displays and,more particularly, to multi-primary Liquid Crystal Displays (LCDs).

BACKGROUND

A Liquid Crystal Display device includes an array of Liquid Crystal (LC)elements, which may be driven, for example, by one or more Thin FilmTransistor (TFT) elements. In some LCD devices, the LC array may includea plurality of column line drivers and a plurality of row line driversto allow controlling each element of the LC array.

The TFTs, the row line drivers and the column line drivers may blockpart of the light provided to the LC array, and consequently reduce thelevel of brightness of the display. Thus, it may be desired to reducethe amount of light blocked by the TFTs, the row line drivers and thecolumn line drivers. Furthermore, it may be desired to reduce the numberof the TFTs, the row line drivers and/or the column line drivers inorder to reduce the cost of the display.

SUMMARY OF EMBODIMENTS OF THE INVENTION

Embodiments of the invention include a method, device and/or system fordisplaying a color image having a plurality of more-than-three primarycolor pixels.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be understood and appreciated more fully from thefollowing detailed description of embodiments of the invention, taken inconjunction with the accompanying drawings of which:

FIG. 1 is a schematic illustration of a more-than-three primary colordisplay system in accordance with exemplary embodiments of theinvention;

FIG. 2 is a schematic illustration of a sub-pixel configurationincluding a repeatable pattern of sub-pixel elements, in accordance withone exemplary embodiment of the invention;

FIGS. 3A and 3B are schematic illustrations of a first 5-primary patternof sub-pixel elements and a second 5-primary pattern of sub-pixelelements, respectively, which may be implemented to form sub-pixelconfigurations in accordance with other exemplary embodiments of theinvention;

FIG. 4 is a schematic illustration of a sub-pixel configurationincluding a repeatable pattern of sub-pixel elements, in accordance withyet another exemplary embodiment of the invention;

FIG. 5 is a schematic illustration of a pattern of sub-pixel elements,which may be implemented to form a sub-pixel configuration in accordancewith additional exemplary embodiments of the invention;

FIGS. 6A, 6B, and 6C are schematic illustrations of a portion of afive-color display embodiment of the present invention having threecolors repeating and two colors alternating, where the pixels are eacharranged on a single horizontal row;

FIG. 6D is a schematic illustration of a portion of another five-colordisplay embodiment of the present invention having three colorsrepeating and two colors alternating, where the pixels are each arrangedon a single horizontal row;

FIGS. 7A, 7B, 7C and 7D are schematic illustrations of a portion ofanother five-color display embodiment of the present invention havingthree colors repeating and two colors alternating, where the pixels areeach arranged on a single horizontal row;

FIGS. 8A, 8B, and 8C are schematic illustrations of portions offive-color display embodiments of the present invention having threecolors repeating and two colors alternating, where the pixels are eacharranged on two horizontal rows;

FIGS. 9A, 9B, and 9C are schematic illustrations of portions offive-color display embodiments of the present invention having threecolors repeating and two colors alternating, where the pixels are eacharranged on a single horizontal row;

FIGS. 10A and 10B are schematic illustrations of portions of five-colordisplay embodiments of the present invention having three colorsrepeating and two colors alternating, where the pixels are each arrangedon two horizontal rows; and

FIGS. 11A and 11B are schematic illustrations of portions of five-colordisplay embodiments of the present invention having three colorsrepeating and two colors alternating, where the pixels are each arrangedon two horizontal rows.

It will be appreciated that for simplicity and clarity of illustration,elements shown in the figures have not necessarily been drawn accuratelyor to scale. For example, the dimensions of some of the elements may beexaggerated relative to other elements for clarity or several physicalcomponents included in one element. Further, where consideredappropriate, reference numerals may be repeated among the figures toindicate corresponding or analogous elements. It will be appreciatedthat these figures present examples of embodiments of the presentinvention and are not intended to limit the scope of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the following description, various aspects of the present inventionwill be described. For purposes of explanation, specific configurationsand details are set forth in order to provide a thorough understandingof the present invention. However, it will be apparent to one skilled inthe art that the present invention may be practiced without the specificdetails presented herein. Furthermore, some features of the inventionrelying on principles and implementations known in the art may beomitted or simplified to avoid obscuring the present invention.

Embodiments of monitors and display devices with more than threeprimaries, in accordance with exemplary embodiments of the invention,are described in International Application PCT/IL02/00452, filed Jun.11, 2002, entitled “DEVICE, SYSTEM AND METHOD FOR COLOR DISPLAY” andpublished 19 Dec. 2002 as PCT Publication WO 02/101644, the disclosureof which is incorporated herein by reference.

Reference is made to FIG. 1, which schematically illustrates amore-than-three primary color display system 100 in accordance withexemplary embodiments of the invention.

According to exemplary embodiments of the invention, system 100 mayinclude a light source 112, and an array of sub-pixel elements. Forexample, system 100 may include an array 113 of liquid crystal (LC)elements (cells) 114, for example, an LC array using Thin FilmTransistor (TFT) active-matrix technology, as is known in the art; andan n-primary-color filter array 116, wherein n is greater than three,which may be, for example, juxtaposed to array 113. System 100 mayinclude any other suitable configuration of sub-pixel elements. System100 may further include electronic circuits 120 (“drivers”) for drivingthe cells of array 113, e.g., by active-matrix addressing, as is knownin the art, According to some exemplary embodiments of the invention, apixel of a color image may be reproduced by sub-pixel elements of morethan three primary colors, wherein each sub-pixel element corresponds toone of the n primary colors. Back-illumination source 112 provides thelight needed to produce the color images. The transmittance of each ofthe sub-pixel elements may be controlled, for example, by the voltageapplied to a corresponding LC cell of array 113, based on image datainput for one or more corresponding pixels, as described below. Ann-primaries controller 118 may be able to receive the image dataincluding sub-pixel data representing pixels of the color image, and toselectively activate at least some of the sub-pixel elements of array113 to produce an attenuation pattern based on the sub-pixel data. Forexample, controller 118 may receive the input data, e.g., in Red (R),Green (G), and Blue (B) or YCbCr format, optionally scale the data to adesired size and resolution, and adjust the magnitude of the signaldelivered to the different drivers based on the input data. Controller118 may be able to convert input image data, e.g., data including RGBimage components or YCbCr data of a pixel, into sub-pixel data of morethan three primary colors, e.g., R, G, B, Yellow (Y), and Cyan (C). Theintensity of white light provided by back-illumination source 112 may bespatially modulated by elements of the LC array, selectively controllingthe illumination of each sub-pixel element according to the image datafor one or more pixels, as described below. The selectively attenuatedlight of each sub-pixel passes through a corresponding color filter ofcolor filter array 116, thereby producing desired color sub-pixelcombinations. The human vision system spatially integrates the lightfiltered through the different color sub-pixel elements to perceive acolor image.

An aperture ratio of a LCD display may be defined as the ratio betweenthe net area of the display and the overall area of the display, whereinthe net area of the display is defined as the overall area of thedisplay excluding a total area of blocking, e.g., a total of areas ofthe display “blocked” by TFTs and the column and row driver lines, as isknown in the art. For example, the total area of blocking of a displayincluding l rows of m sub-pixel elements, wherein each sub-pixel elementincludes one TFT, wherein each row includes one row driver line, andwherein each column includes one column driver, may be calculated asfollows:m*L_(column)*t_(column)+l*L_(row)*t_(row)+l*m*S_(tft)  (1)

wherein S_(tft) denotes the blocking area of each TFT, L_(row) andt_(row) denote the length and width of each row driver line,respectively, and L_(column) and t_(column) denote the length and widthof each column driver line, respectively. Accordingly, the overall areaof the display may be approximately L_(column)*L_(row), and the apertureratio of the display may be calculated assuming an aspect ratioAR=L_(row)/L_(column).

It will be appreciated by those skilled in the art that a higher totalarea of blocking may correspond to a lower brightness level of thedisplay, since a larger amount of the light provided to the display isblocked by the TFTs and/or driver lines.

According to some exemplary embodiments of the invention, system 100 maybe implemented for reproducing a color image having a plurality ofmore-than-three primary color pixels, using an array of sub-pixelelements of at least four different primary colors, wherein the totalnumber, denoted S_(T), of sub-pixel elements in the array issignificantly smaller than a product P=s*n, wherein s denotes the numberof more-than-three-primary color pixels in the image, and wherein ndenotes the number of the at least four different primary colors, asdescribed in detail below. For example, the number of sub-pixel elementsin the array as a fraction of the product P may be related to the numberof the four or more primary colors. The array may include, for example,sub-pixel elements arranged in at least one repeatable color sequence ofsub-pixel elements of at least three primary colors, and the totalnumber of sub-pixel elements in the array as a fraction of the product Pmay be equal to approximately the number of sub-pixel elements in thecolor sequence divided by the number of the four or more primary colors,as described below.

The human vision system may perceive different primary colors indifferent levels of spatial resolution. For example, the human visionmay perceive some primary colors, e.g., blue and cyan, in asubstantially lower level of spatial resolution in comparison to theperceived spatial resolution level of other primary colors, e.g., green,yellow and red. Thus, according to embodiments of the invention, some ofthe primary colors, e.g., blue and/or cyan, may be displayed in a lowerspatial resolution, e.g., using a smaller number of sub-pixel elements,as compared to other primary colors, e.g., red, green and/or yellow,without significantly affecting the over-all resolution of the colorimage perceived by the human vision system, as described below.

According to exemplary embodiments of the invention, the sub-pixelelements of array 113 may be arranged in a predetermined configurationincluding a predetermined repeatable pattern including a predetermined,fixed, number of sub-pixel elements, each corresponding to one of the nprimary colors. For example, array 113 may include sub-pixel elements ofat least four different primary colors arranged in at least first andsecond repeatable color sequences of sub-pixel elements of at leastthree primary colors, wherein the first color sequence includes at leastone sub-pixel element of a primary color not included in the secondsequence, as described below. Accordingly, the pattern may include asmaller number of sub-pixel elements corresponding to one or morepredetermined primary colors compared to the number of sub-pixelelements corresponding to other primary colors. According to some ofthese exemplary embodiments, drivers 120 of some of the sub-pixelelements, e.g., the drivers of sub-pixel elements corresponding to theone or more predetermined primary colors, may be provided with a valuecorresponding to a combination of sub-pixel data of more than one pixel,as described below. This manipulation of image data may be performed,for example, by controller 118.

Reference is made to FIG. 2, which schematically illustrates aconfiguration 200 of sub-pixel elements in a five-primary display deviceincluding a repeatable pattern 201, in accordance with one exemplaryembodiment of the invention.

Pattern 201 may include sub-pixel elements corresponding to five primarycolors, e.g., red, yellow, green, cyan and blue, arranged in a rowincluding eight sub-pixel elements.

According to an exemplary embodiment, pattern 201 may include a smallernumber of sub-pixel elements corresponding to each of the blue and cyanprimary colors in comparison to the number of sub-pixel elementscorresponding to each of the red, green and yellow primary colors, asdescribed below.

Pattern 201 may include two sub-pixel elements, e.g., sub-pixel elements211 and 215, corresponding to the red primary color, two sub-pixelelements, e.g., sub-pixel elements 212 and 216, corresponding to theyellow primary color, two sub-pixel elements, e.g., sub-pixel elements213 and 217, corresponding to the green primary color, one sub-pixelelement, e.g., sub-pixel element 214 corresponding to the cyan primarycolor, and one sub-pixel element, e.g., sub-pixel element 218,corresponding to the blue primary color.

According to this exemplary embodiment, configuration 200 may includesub-pixel elements arranged in at least first and second repeatablecolor sequences, e.g., color sequences 230 and 232. Sequence 230 mayinclude at least one sub-pixel element, e.g., element 214, of a primarycolor, e.g., cyan, not included in sequence 232. Sequence 232 mayinclude at least one sub-pixel element, e.g., element 218, of a primarycolor, e.g., blue, not included in sequence 230.

According to this exemplary embodiment, sequences 230 and 232 may eachinclude sub-pixel elements of a predetermined sub-sequence of some ofthe primary colors, for example, a red-yellow-green sub-sequence.According to other embodiments of the invention one or more of therepeatable color sequences may include any other predetermined sub-colorsequence.

According to some exemplary embodiments of the invention, each pixel ofthe color image may be reproduced by one or more sub-pixel elements ofconfiguration 200. For example, a first pixel of the color image may bereproduced by sub-pixel elements 214, 215, 216, 217, and/or 218; and asecond pixel, e.g., adjacent to the first pixel, may be reproduced bysub-pixel elements 218, 233, 234, 235 and/or 236. According to someembodiments of the invention, one or more sub-pixel elements ofconfiguration 200, for example, sub-pixel elements corresponding to theblue and/or cyan primary colors, e.g., sub-pixel elements 214 and/or218, may be activated based on a value determined by a combination ofsub-pixel data corresponding to two or more pixels of the color image.Other sub-pixel elements of configuration 200, for example, sub-pixelelements corresponding to the green, red and/or yellow primary colors,e.g., sub-pixel elements 211, 212, 213, 215, 216, 217, 233, 234 and/or235, may be activated based on sub-pixel data corresponding to one ormore pixels. For example, one or more drivers, e.g. of drivers 120 (FIG.1), of a sub-pixel element corresponding to one or more of the red,green or yellow primary colors, respectively, may be provided with avalue corresponding to red, green and yellow sub-pixel data,respectively, of one or more pixels. This data arrangement may beprovided by controller 118 (FIG. 1). A driver, e.g. of drivers 120 (FIG.1), of a sub-pixel element corresponding to a primary color not includedin one of sequences 230 and 232 may be provided with a value determinedby a combination of sub-pixel data of two or more pixels. For example, adriver of a sub-pixel element corresponding to the cyan primary colormay be provided with a value determined by a combination, e.g., anarithmetic average, a weighted average and/or any other suitablecombination, of cyan sub-pixel data of two or more pixels. A driver,e.g. of drivers 120 (FIG. 1), of a sub-pixel element corresponding to ablue sub-pixel may be provided, for example, with a value determined bya combination, e.g., an arithmetic average, a weighted average and/orany other suitable combination, of blue sub-pixel data of two or morepixels. The two or more pixels may include, for example, two or moreneighboring pixels, e.g., two or more vertically, horizontally and/ordiagonally adjacent pixels, or any other two or more pixels of the colorimage. Thus, it will be appreciated by those skilled in the art thatsince the sub-pixel elements of pattern 201 may be activated toreproduce two pixels, the size of an effective pixel corresponding toconfiguration 200 (“the effective pixel size”) may be equal to half thesum of the areas of the sub-pixel elements of pattern 201. Controller118 (FIG. 1) may rearrange the sub-pixel data to provide the desiredsequences of values to drivers 120.

According to exemplary embodiments of the invention, the size of some ofthe sub-pixel elements may be different than the size of other sub-pixelelements in order to achieve a desired white balance of the display. Forexample, the area covered by each sub-pixel element corresponding to theblue and/or the cyan primaries may be larger than the area covered byeach sub-pixel element corresponding to the red, yellow and/or greenprimaries.

It will be appreciated by those skilled in the art that a displaysystem, e.g., system 100 (FIG. 1), implementing configuration 200 forreproducing a color image including l rows of s 5-primary pixels, mayinclude 4*s column driver lines and l row driver lines. Such a displaymay also include 4*s*l TFTs, e.g., one TFT located on each sub-pixelelement. Accordingly, a total blocking area of such a display may beequal to:4*s*L_(column)*t_(column)+l*L_(row)*t_(row)+4*l*s*S_(tft)  (2)

It will be appreciated by those skilled in the art that a displayaccording to the exemplary embodiments described above, may include asmaller number of column driver lines and a smaller number of TFTscompared to the number of column driver lines, e.g., 5*s, and the numberof TFTs, e.g., 5*s*l, of other 5-primary display systems, e.g., whereinsub-pixel elements of five primary colors are used for reproducing eachpixel. Consequently, a display according to the exemplary embodimentsdescribed above, may also have a relatively smaller total blocking arearesulting in a higher brightness level, compared to the total blockingarea, e.g., 5*s*L_(column)*t_(column)+l*L_(row)*t_(row)+5*l*s*S_(tft),and the resulting brightness level of other 5-primary display systems.For example, a 1280×720 display having a 16:9 aspect ratio, i.e.,s=1280, l=720 and L_(row)=16/9*L_(column), may have an aperture ratio ofapproximately 70%, i.e., a total area of blocking of approximately 30%,if sub-pixel elements of five primary colors are used for reproducingeach pixel. Assuming the total area of blocking includes 6% TFTblocking, and 24% driver lines blocking, and assumingt_(row)=t_(column), it will be appreciated by those skilled in the artthat implementing sub-pixel arrangement 200 may reduce the TFT blockingto approximately 5%, and the driver line blocking to approximately 20%.Accordingly, the aperture ratio of such a display implementingarrangement 200 may be increased by approximately 5%, e.g. to anapproximate value of 75%. Furthermore, implementing sub-pixelarrangement 200 may reduce the number of column drivers by approximately20%, which may result in a reduction in a data rate required foractivating the sub-pixel elements of pattern 200.

It will be appreciated by those skilled in the art that according toother embodiments of the invention, any other suitable pattern ofsub-pixel elements, e.g., including any suitable two or more repeatablecolor sequences, may be implemented by display system 100 (FIG. 1) toform a sub-pixel configuration similar to configuration 200, e.g., asdescribed below.

Reference is also made to FIGS. 3A and 3B which schematically illustratea first 5-primary pattern 300 of sub-pixel elements and a second5-primary pattern 310 of sub-pixel elements, respectively, which may beimplemented to form configuration 200 according to other exemplaryembodiments of the invention.

Pattern 300 may include two different rows, e.g., row 302 and row 304.Row 302 may include sub-pixel elements arranged, for example, in theorder “yellow-green-red-cyan-yellow-green-red-blue”. Row 304 may includesub-pixel elements arranged, for example, in the order“yellow-green-red-blue-yellow-green-red-cyan”. Accordingly, pattern 300may include a first color sequence 303, e.g., including sub-pixelselements of the primary colors “yellow-green-red-cyan”, and a secondcolor sequence 305, e.g., including sub-pixels elements of the primarycolors “yellow-green-red-blue”.

Pattern 310 may include two different rows, e.g., row 312 and row 314.Row 312 may include sub-pixel elements arranged, for example, in theorder “red-yellow-green-cyan-red-yellow-green-blue”. Row 314 may includesub-pixel elements arranged, for example, in the order“red-yellow-green-blue-red-yellow-green-cyan”. Accordingly, pattern 310may include a first color sequence 313, e.g., including sub-pixelselements of the primary colors “red-yellow-green-cyan”, and a secondcolor sequence 315, e.g., including sub-pixels elements of the primarycolors “red-yellow-green-blue”. According to other embodiments of theinvention pattern 300 and/or pattern 310 may include any other suitableconfiguration of sub-pixel elements.

It will be appreciated by those skilled in the art that a pattern, e.g.,pattern 300 or pattern 310, wherein the location of the cyan and blueprimary colors is interchanged along the columns, may be implemented toachieve a more uniform color distribution across the display.

According to some embodiments of the invention, an effective pixel ofthe color image may be reproduced by sub-pixel elements of more than onerow, as described below.

Reference is made to FIG. 4, which schematically illustrates aconfiguration 400 of sub-pixel elements in a five-primary display deviceincluding a repeatable pattern 401, in accordance with another exemplaryembodiment of the invention.

Pattern 401 may include sub-pixel elements corresponding to five primarycolors, e.g., red, yellow, green, cyan and blue, arranged in twoadjacent rows, e.g., rows 410 and 420.

According to an exemplary embodiment, pattern 401 may include a smallernumber of sub-pixel elements corresponding to each of the blue and cyanprimary colors in comparison to the number of sub-pixel elementscorresponding to each of the red, green and yellow primary colors, asdescribed below.

Row 420 may include four sub-pixel elements 412, 416, 415, and 434corresponding to the primary colors red, yellow, red and yellow,respectively. Row 410 may include four sub-pixel elements 413, 414, 417,and 418 corresponding to the primary colors green, cyan, green and blue,respectively.

According to this exemplary embodiment, the sub-pixel elements ofpattern 401 may be arranged in at least first and second repeatablecolor sequences, e.g., color sequences 460 and 462. Sequence 460 mayinclude at least one sub-pixel element, e.g., element 414, of a primarycolor, e.g., cyan, not included in sequence 462. Sequence 462 mayinclude at least one sub-pixel element, e.g., element 418, of a primarycolor, e.g., blue, not included in sequence 460.

According to this exemplary embodiment, sequences 460 and/or 462 mayinclude sub-pixel elements of a predetermined sub-sequence of some ofthe primary colors, for example, a red-yellow-green sub-sequence.

According to some exemplary embodiments of the invention, each pixel ofthe color image may be reproduced by one or more sub-pixel elements ofconfiguration 400. For example, a first pixel of the color image may bereproduced by sub-pixel elements 416, 415, 414, 417 and/or 418; and asecond pixel, e.g., adjacent to the first pixel, may be reproduced bysub-pixel elements 434, 418, 433, 435 and/or 436. According to someembodiments of the invention, one or more sub-pixel elements ofconfiguration 400, for example, sub-pixel elements corresponding to theblue and/or cyan primary colors, e.g., sub-pixel elements 414 and/or418, may be activated based on a value determined by a combination ofsub-pixel data corresponding to two or more pixels of the color image.Other sub-pixel elements of configuration 400, for example, sub-pixelelements corresponding to the green, red and/or yellow primary colors,e.g., sub-pixel elements 416, 415, 417, 434, 435 and/or 433, may beactivated based on sub-pixel data corresponding to one or more pixels.For example, one or more drivers, e.g. of drivers 120 (FIG. 1), of asub-pixel element corresponding to one or more of the red, green and/oryellow primary colors, respectively, may be provided a valuecorresponding to red, green and/or yellow sub-pixel data, respectively,of one or more pixels. This data arrangement may be provided bycontroller 118 (FIG. 1). A driver, e.g. of drivers 120 (FIG. 1), of asub-pixel element corresponding to the cyan primary color may beprovided with a value determined by a combination, e.g., an arithmeticaverage, a weighted average and/or any other suitable combination, ofcyan sub-pixel data corresponding to two or more pixels. A driver, e.g.of drivers 120 (FIG. 1), of a sub-pixel element corresponding to a bluesub-pixel may be provided with a value determined by a combination,e.g., an arithmetic average a weighted average and/or any other suitablecombination, of blue sub-pixel data corresponding to two or more pixels.The two or more pixels may include, for example, two or more neighboringpixels, e.g., two or more vertically, horizontally and/or diagonallyadjacent pixels, or any other two or more pixels of the color image.Thus, it will be appreciated by those skilled in the art that since thesub-pixel elements of pattern 401 may be activated to reproduce twopixels, the effective pixel size corresponding to configuration 400 maybe equal to half the sum of the areas of the sub-pixel elements ofpattern 401. Controller 118 (FIG. 1) may rearrange the sub-pixel data toprovide the desired sequences of values to drivers 120.

According to exemplary embodiments of the invention, the size of some ofthe sub-pixel elements may be different from the size of other sub-pixelelements in order to achieve a desired white balance of the displayedimage. For example, the area of each sub-pixel element corresponding tothe blue and/or the cyan primaries may be larger than the area of eachsub-pixel element corresponding to the red, yellow and/or greenprimaries.

It will be appreciated by those skilled in the art, that a displaysystem, e.g., system 100 (FIG. 1), implementing configuration 400 forreproducing a color image including l rows of s 5-primary pixels, mayinclude 2*s column driver lines and 2*l row driver lines. Such a displaymay also include 4*s*l TFTs, e.g., one TFT located on each sub-pixelelement. Accordingly, a total blocking area of such a display may beequal to:2*s*L_(column)*t_(column)+2*l*L_(row)*t_(row)+4*l*s*S_(tft)  (3)

It will be appreciated by those skilled in the art that the over-allcost of driver lines of a 5-primary display implementing configuration400 may be lower compared to the cost of driver lines of a conventional3-primary LCD display, e.g., a display including 3*s column driver linesand l row driver lines, because the cost of a column driver line isgenerally higher than the cost of a row driver line. It will also beappreciated by those skilled in the art, that the over-all cost of a5-primary display implementing configuration 400 may be lower comparedto the over-all cost of some four-primary displays, wherein sub-pixelelements of four or five primaries are used for reproducing each pixel,and of some five-primary displays, wherein sub-pixel elements of fiveprimary colors are used for reproducing each pixel.

It will further be appreciated by those skilled in the art that adisplay according to the exemplary embodiments described above may havea total blocking area of2*s*L_(column)*t_(column)+2*l*L_(row)*t_(row)+4*l*s*S_(tft), compared tothe total blocking area of a conventional 3-primary LCD display, e.g.,3*s*L_(column)*t_(column)+l*L_(row)*t_(row)+3*l*s*S_(tft). Furthermore,if L_(row)=16/9*L_(column), s=1280, and l=720, an aperture ratio ofapproximately 78% may be achieved if configuration 400 is implemented,which is higher than the achievable aperture ratio, e.g., 75%,corresponding to configuration 200, which in turn is higher than theachievable aperture ratio, e.g., 70%, corresponding to a five-primarydisplay wherein sub-pixel elements of five primary colors are used forreproducing each pixel.

It will be appreciated by those skilled in the art that according toother embodiments of the invention, any other suitable pattern ofsub-pixel elements, e.g., including any suitable two or more repeatablecolor sequences, may be implemented by display system 100 (FIG. 1) toform a configuration similar to configuration 400, e.g., as describedbelow.

Reference is also made to FIG. 5, which schematically illustrates a5-primary pattern 500 of sub-pixel elements, which may be implemented toform a sub-pixel configuration according to other exemplary embodimentsof the invention.

Pattern 500 may include four rows, e.g., row 502, row 504, row 506, androw 508. Row 502 and row 506 may be identical and may each include a2-primary sequence, for example, a sequence “red-yellow-red-yellow”. Row504 and row 508 may include a 3-primary sequence, e.g.,“green-cyan-green-blue” and a 3-primary sequence, e.g.,“green-blue-green-cyan”, respectively. It will be appreciated by thoseskilled in the art that a pattern, e.g., pattern 500, wherein thelocation of the cyan and blue primary colors is interchanged along thecolumns, may be implemented to achieve a more uniform color distributionacross the display.

Some exemplary embodiments of the invention, e.g., as are describedabove, may relate to a controller, e.g., controller 118 (FIG. 1) able toprovide a driver of a sub-pixel element corresponding to the cyanprimary color with a value determined based on a combination ofsub-pixel data corresponding to the cyan primary color of two or morepixels, and/or to provide a driver of a sub-pixel element correspondingto the blue primary color with a value determined based on a combinationof sub-pixel data corresponding to the blue primary color of two or morepixels. However, other exemplary embodiments of the invention mayinclude a controller, e.g., controller 118 (FIG. 1) able to provide thedrivers of one or more sub-pixel elements with a value determined basedon any other desired combination of sub-pixel data of one or morepixels, e.g., as described below.

According to some embodiments of the invention, controller 118 (FIG. 1)may be able to provide drivers, e.g., drivers 120 (FIG. 1),corresponding to sub-pixel elements of at least first and second colorsequences, e.g., as are described above, based on sub-pixel datacorresponding to at least first and second pixels of the color image.Controller 118 (FIG. 1) may be able, for example, to activate at leastone sub-pixel element of at least one of the first and second sequences,based on a value determined by a combination of sub-pixel data of atleast the first and second pixels, as described below.

According to some exemplary embodiments of the invention, controller 118(FIG. 1) may be able to activate a sub-pixel element of the first/secondsequence based on a value determined by a combination of sub-pixel dataof the sub-pixel element to be activated and the primary color notincluded in the first/second sequence. For example, controller 118(FIG. 1) may be able to provide the drivers of green sub-pixel elementswith a value determined based on a combination of green sub-pixel dataand cyan sub-pixel data of a pixel; and/or to provide the drivers ofblue sub-pixel elements with a value determined based on a combinationof blue sub-pixel data and cyan sub-pixel data of a pixel. Alternativelyor additionally controller 118 may be able to provide the drivers ofcyan sub-pixel elements with a value determined based on a combinationof blue sub-pixel data and cyan sub-pixel data of a pixel; and/or toprovide the drivers of red sub-pixel elements with a value determinedbased on a combination of blue sub-pixel data and red sub-pixel data ofa pixel.

In some embodiments, the green, blue and cyan primaries of a display,e.g., display 100 (FIG. 1) may be represented by predetermined green,blue and cyan primary color vectors in the XYZ color space, denoted{right arrow over (P)}_(G), {right arrow over (P)}_(B), and {right arrowover (P)}_(C), respectively.

According to some exemplary embodiments of the invention, a combination,e.g., a linear combination, of the green and blue primary color vectors,may be implemented to produce a color approximately equivalent orcomparable to the cyan primary color. A desired linear combination maybe determined, for example, using the following equation:{right arrow over (P)} _(C) ≅β{right arrow over (P)} _(B) +γ{right arrowover (P)} _(G)  (4)wherein β and γ denote parameters relating to the linear contributionsof the blue and green primary colors, respectively. It will beappreciated that the linear combination according to Equation 4 may beused to reproduce a color equivalent to the cyan primary color, e.g., ifthe chromaticity value of the cyan primary color is located on a lineconnecting the chromaticity values of the green and blue primary colors,or comparable to the cyan primary color, e.g., if the chromaticity valueof the cyan primary color is located off but relatively proximal to theline connecting the chromaticity values of the green and blue primarycolors.

As described above, some pixels of display 100 may be reproduced by aplurality of sub-pixel elements not including a blue sub-pixel element(“non-blue sub-pixel elements”), and/or some pixels may be reproduced bya plurality of sub-pixel elements not including a cyan sub-pixel(“non-cyan sub-pixel elements”). According to exemplary embodiments ofthe invention, controller 118 (FIG. 1) may be able to provide thedrivers of one or more non-cyan sub-pixel elements with a valuedetermined based on cyan sub-pixel data. For example, controller 118(FIG. 1) may provide the drivers of blue and/or green sub-pixel elementsfor reproducing a pixel with signals B′ and G′, respectively, e.g.,according to the following equation set:B′=B+C·βG′=G+C·γ  (5)wherein B, G, and C denote the blue, green and cyan image components ofthe pixel to be reproduced. According to some exemplary embodiments ofthe invention, the values of one or both of B′ and/or G′ may be“clipped”, i.e., set to a maximal producible value of the blue and greenprimary colors, respectively, e.g., if the values of B′ and/or G′calculated according to Equation 5 exceed the maximal producible valueof the blue and/or green primary colors, respectively.

It will be appreciated by those skilled in the art, that activating blueand/or green sub-pixel elements based on cyan sub-pixel data may improvethe perceived spatial resolution of the cyan primary color and/or reducea perceived luminance variation between a pixel reproduced by non-bluesub-pixel elements and a pixel reproduced by non-cyan sub-pixelelements.

According to some exemplary embodiments of the invention, it may bedesired to reduce a color shift, e.g., a cyan color shift, which mayresult, for example, from activating one or more non-cyan sub-pixelelements based on a value determined by cyan sub-pixel data. Such acolor shift may be reduced, according to some exemplary embodiments ofthe invention, by activating a blue sub-pixel element, e.g., of a firstcolor sequence, based on a corrected value determined by a combination,e.g., a sum, of blue sub-pixel data of a first pixel and a bluecorrection component, ΔB; activating a green sub-pixel element, e.g., ofthe first color sequence, based on a corrected value determined by acombination, e.g., a sum, of green sub-pixel data of the first pixel anda green correction component, ΔG; and activating a cyan sub-pixelelement, for example, of a second color sequence, e.g., adjacent to thefirst color sequence, based on a corrected value determined by acombination of, e.g., a difference between, cyan sub-pixel data of asecond pixel and a cyan correction component, ΔC, as described below.

According to some exemplary embodiments of the invention, the correctioncomponents ΔC, ΔB, and ΔG may be determined such that the luminance ofthe cyan primary color reproduced by the cyan sub-pixel element issubstantially equal to the sum of the luminance of the blue primarycolor reproduced by the blue sub-pixel element and the luminance of thegreen primary color resulting from the green correction component ΔG.Additionally, it may be desired that the amount of the cyan colorresulting from the cyan correction component ΔC, will be substantiallyequal to the amount of a cyan-equivalent color reproduced by the greenand blue sub-pixel elements, e.g., the sum of the amount of blue colorresulting from the blue correction component, ΔB, and the amount of thegreen color resulting from the green correction component, ΔG. Forexample, the correction components may be determined using the followingequations:(C−ΔC)·Y _(C)=(B+ΔB)·Y _(B) +ΔG·Y _(G)  (6)ΔC·{right arrow over (P)} _(C) =ΔB·{right arrow over (P)} _(B)+ΔG·{right arrow over (P)} _(G)  (7)wherein Y_(C), Y_(B), and Y_(G) denote the luminance of the cyan, blueand green primary colors.

Substituting Equation 4 in Equation 7 and re-arranging terms may yieldthe following equations:ΔB=βΔC  (8)ΔG=γΔC  (9)

Substituting Equations 8 and 9 in Equation 6 and rearranging terms mayyield the following equation:

$\begin{matrix}{{\Delta\; C} = \frac{{C \cdot Y_{C}} - {B \cdot Y_{B}}}{Y_{C} + {\beta \cdot Y_{B}} + {\gamma \cdot Y_{G}}}} & (10)\end{matrix}$

According to exemplary embodiments of the invention, controller 118(FIG. 1) may determine a value for the cyan correction component ΔC,e.g., by substituting in Equation 10 the primary color luminance valuesY_(C), Y_(B), and Y_(G), predefined parameters β and γ, and the cyan anda value corresponding to the blue sub-pixel data of the first pixel.Controller 118 may additionally determine a value for the bluecorrection component ΔB and/or a value for the green correctioncomponent ΔG, e.g., using Equations 8 and 9. Controller 118 may providethe blue, green and cyan sub-pixel elements with corrected values, e.g.,based on the correction components ΔB, ΔG, and ΔC, e.g., as describedabove.

According to some exemplary embodiments of the invention, the correctedvalue provided to the blue sub-pixel and/or the corrected value providedto the green sub-pixel may be clipped, e.g., if the corrected valueprovided to the blue sub-pixel element and/or the corrected valueprovided to the green sub-pixel element exceed the maximal produciblevalue of the blue and/or green primary colors, respectively.

Some exemplary embodiments of the invention, e.g., as are describedabove, relate to activating green and/or blue sub-pixel elements basedon cyan sub-pixel data; and/or activating green, blue and/or cyansub-pixel elements based on corrected values. However, other embodimentsof the invention may analogously be implemented for activating one ormore other sub-pixel elements, e.g., a cyan sub-pixel element or cyanand red sub-pixel elements, based on other sub-pixel data, e.g., bluesub-pixel data; and/or activating other sub-pixel elements, e.g., cyanred and blue sub-pixel elements, based on corrected values. For example,in other embodiments, one or more sub-pixel elements may be activatedbased on any suitable combination of sub-pixel data of one or morepixels, e.g., a combination corresponding to a spatial function of oneor more pixels.

Various embodiments of the invention may also use different alternatingcolors than cyan-blue, as described above. For example, in oneembodiment of the invention, depicted in FIG. 6A, the display maycomprise alternating pixels 610 and 620. A first pixel 610 may includesub-pixel elements red, green, blue and yellow. A second pixel 620,adjacent to the first pixel 610, may include sub-pixel elements cyan,red, green and blue. It will be recognized that pixels such as pixels610 and 620 may repeat alternatingly to cover substantially the entiredisplay.

According to embodiments of the invention having alternating cyan-yellowin adjacent pixels, depicted in FIG. 6A, in a pixel containing theyellow sub-pixel, cyan may be produced by modifying the intensity valuesof the green and blue sub-pixels to include a cyan component, asdiscussed, for example at Equation (5) and Equations (8) to (10), aboveor any of the other above equations. Likewise, in a pixel containing thecyan sub-pixel, yellow may be produced by modifying the intensity valuesof the green and red sub-pixels to include a yellow component, using theequations above for yellow using red and green sub-pixels. Thus, forexample, in the arrangement of FIG. 6A, the blue sub-pixel will carryblue information and a portion of cyan information; the red sub-pixelwill carry red information and a portion of yellow information; and thegreen sub-pixel will carry green information and a portion of both cyanand yellow information. Embodiments of the present invention may alsoenable enhancement of white or luminance information by modifying twosets of sub-pixels independently, e.g., modifying RGB and YC sets ofsub-pixels to enhance the luminance resolution of the resulting image.

Displays according to the present invention may be operated in at leasttwo modes. In a first mode, the number of data pixels per line in thedata stream may be identical to the number of display pixels. In suchfirst mode, each data pixel may be converted into sub-pixel values forwithin each display pixel. This conversion may be performed bytranslating the three-dimensional input for each of the display pixelsto the sub-pixel values representing the colors within eachcorresponding pixel. For example, using the embodiment of FIG. 6A, RGBinput data may be converted into RGBY display data for a pixelcontaining yellow, and into RGBC display data for a pixel containingcyan. Alternatively, the three-dimensional input may be converted tocolor values for all n colors for each pixel, and based on thesub-pixels included in each particular pixel, further processing may beapplied to determine the intensity values for each of the sub-pixels inthe pixel, as discussed in the above equations, e.g., Equations (5) and(8) to (10), and similar equations for yellow using red and greensub-pixels.

In a second mode of operation, for example, when the display is amonitor provided by graphic data from a computer, data may be providedat a higher resolution than that of the display. For example, the numberof data pixels per line may be greater than the number of display pixelsin that line. In another example, the data may be given in vectorformat, e.g., infinite resolution, and then be rendered directly to thedisplay format. Such data may be, for example, text or graphic data inmany computer applications. Accordingly, the high resolution input datastream may be sampled more than once per display pixel, thus enhancingthe resolution. Thus, for each display pixel, more than one input datapoint may be obtained.

For example, in the case of black-and-white data, or gray scale data,the data may be sampled three times per two sub-pixels of FIG. 6A: atthe center of the RGB sub-pixels, e.g., at the G sub-pixels, of thefirst and second pixels; and at the center of the YC sub-pixels, e.g.,at the junction of the Y sub-pixel of the first pixel and the Csub-pixel of the second pixel. The black-and-white data may then bereconstructed by the two RGB triads in the first and second pixels andthe CY sub-pixel combination. For a general color input, a separation toa luminance and color channels may be performed, the luminance channelprocessed, and sampled at the higher spatial frequency, while thechromatic channels processed at the display resolution.

In another example using FIG. 6A, yellow information may be sampled anddisplayed at three locations for each two adjacent pixels, e.g., at eachyellow sub-pixel and at each red and green pair of sub-pixels, asdepicted in FIG. 6B. Similarly, cyan information may be sampled anddisplayed at three locations for each two adjacent pixels, e.g., at eachcyan sub-pixel and at each blue and green pair of sub-pixels, asdepicted in FIG. 6C.

It will be recognized that the embodiment of the invention depicted inFIG. 6A represents an n-color display, n representing the total numberof colors represented by the sub-pixels, where n=5. It will berecognized that in various embodiments of the invention, n may be anynumber greater than three. Each pixel comprises a number m ofsub-pixels, where not all of n pixels are represented in each pixel. Inthe embodiment depicted in FIG. 6A, therefore, m=4.

It will be recognized that the arrangement of sub-pixels depicted in theembodiment of FIG. 6A may be modified within the spirit of theinvention. In one embodiment, n=5 and m=3, with one color repeating, forexample, red, and two colors alternating, for example, blue-yellow inone pixel and cyan-green in the next pixel. In another embodiment, n=6and m=4, with two colors repeating, for example, red and green, and twocolors alternating, for example, blue-yellow in one pixel andcyan-magenta in the next pixel. In yet another embodiment, n=6 and m=4,with one sub-pixel alternating among cyan, yellow and magenta in each ofthree adjoining pixels. In yet another embodiment, n=6 and m=5, withred, green and blue repeating, and two sub-pixels in each pixelalternating among cyan and yellow, yellow and magenta, and cyan andmagenta.

It will be further recognized that the particular ordering of thesub-pixels within each pixel may provide certain advantages. Forexample, in the embodiment depicted in FIG. 6A, it will be recognizedthat the enhancement of white, yellow and cyan may be distributed evenlyby the placement of the sub-pixels.

Thus, for example, in the embodiment depicted at FIG. 6A, the yellowinformation may be carried by red and green sub-pixels, and by theyellow sub-pixels. Thus, it will be noted that the red and greensub-pixels are adjacent each other in both pixels 610 and 620. Moreover,the yellow information units, e.g., red-green sub-pixel pairs and theyellow sub-pixels, are equidistant from each other on any side. In orderto demonstrate this feature, FIG. 6B depicts the sub-pixels in FIG. 6Athat carry yellow information, omitting sub-pixels that carry no yellowinformation. It may be observed that red-green sub-pixel pairs andyellow sub-pixels are separated by one sub-pixel, thereby producing auniform distribution of yellow information.

Similarly, for example, in the embodiment depicted at FIG. 6A, the cyaninformation may be carried by blue and green sub-pixels, and by the cyansub-pixels. Thus, it will be noted that the blue and green sub-pixelsare adjacent each other in both pixels 610 and 620. Moreover, the yellowinformation units, e.g., red-green sub-pixel pairs and the yellowsub-pixels, are equidistant from each other on any side. In order todemonstrate this feature, FIG. 6C depicts the sub-pixels in FIG. 6A thatcarry cyan information, omitting sub-pixels that carry no cyaninformation. It may be observed that blue-green sub-pixel pairs and cyansub-pixels are separated by one sub-pixel, thereby producing a uniformdistribution of cyan information.

Another embodiment of the invention is depicted at FIG. 6D. It will benoted that in this embodiment, as with FIG. 6A, RGB sub-pixels arelocated in each pixel. However, the yellow and cyan are not adjacent toeach other at the border of the adjacent pixels, but rather, the yellowand cyan sub-pixels are separated by a set of RGB subpixels.Accordingly, as with FIG. 6A, RGB colors may be evenly distributed, butthe yellow and cyan may have different distribution than in FIG. 6A.

In this configuration, the luminance (white) signal may be reproducedwith higher resolution using the RG, Y, and C units, while the Bsub-pixels may be used to compensate for color deviation from white.

Another embodiment of the invention is depicted in FIG. 7A. Theconfiguration depicted in FIG. 7A may enable even distribution of highintensity, e.g., green, yellow and cyan subpixels. It will be noted thatin the arrangement of FIG. 7A, every alternate location contains eithera green, yellow or cyan subpixel.

The configuration of the invention depicted in FIG. 7A may also enableincreased white, yellow and cyan resolution. In this embodiment of theinvention, white resolution may be enhanced by modifying sets of threeadjacent sub-pixels. FIG. 7B depicts the embodiment of FIG. 7A dividedinto overlapping sets of three adjacent sub-pixels. In the illustrationof FIG. 7B, each of the red and blue sub-pixels are “divided” into twohalves, with each of the halves belonging to a different set ofsub-pixels, each set producing white. Thus, for example, the first threesub-pixels of pixel 710 include R/2, G and B/2. These sub-pixelstherefore, may be used to produce a white enhancement, albeit a slightlygreen white, insofar as the green has twice as much representation asthe red and blue. The next overlapping set of three sub-pixels is B/2,Y, and B/2, which yields white. The next set, B/2, G, and R/2 wouldagain produce a greenish white. Finally, the set of sub-pixelscomprising R/2, C, and R/2 would yield a slightly reddish white. Forpurposes of enhanced resolution, these slight color variations, e.g.,greenish, reddish, are not important.

In addition to the above white enhancement, the embodiment of FIG. 7Amay be used to enhance yellow and cyan resolution. Reference is made tothe illustration of FIG. 7C, which depicts sub-pixels in pixels 710 and720 having yellow information. For yellow resolution, it will be notedthat red and green sub-pixel pairs may be kept adjacent to each other,and are equidistant from the yellow sub-pixels and from each other.Reference is made to the illustration of FIG. 7D, which depictssub-pixels in pixels 710 and 720 having cyan information. For cyanresolution, it will be noted that blue and green sub-pixel pairs may bekept adjacent to each other, and are equidistant from the cyansub-pixels and from each other.

Some embodiments of the invention may form pixels by using sub-pixels inmore than one row. Reference is made to FIGS. 8A, 8B and 8C, whichdepict double-row pixel embodiments of the invention in which sub-pixelsare arranged in a square matrix to form a pixel. In all of FIGS. 8A, 8Band 8C, pixels alternate horizontally between RGBY and RGBC. In FIG. 8A,the red, green and blue sub-pixels are in the same location in allpixels, and the fourth place alternates between yellow and cyan. FIG. 8Bis similar to FIG. 8A in most regards, however, it will be recognizedthat the adjacency of the red and green sub-pixels may produce greatereffectiveness in yellow enhancement, and the adjacency of blue and greensub-pixels may produce greater effectiveness in cyan enhancement.

In FIG. 8C, the locations of red, green and blue sub-pixels changebetween the RGBY and RGBC sub-pixels. It will be recognized that in theembodiment of FIG. 8C, there is a vertical shift between horizontallyadjacent pixels, thereby maintaining a relatively uniform distancebetween sub-pixels of the same color in adjacent pixels for evenness ofdisplay. Thus, the distance between any two red sub-pixels inhorizontally adjacent pixels is the distance of two sub-pixelshorizontally and one sub-pixel vertically. Other configurations arepossible consistent with the present invention, provided that in eachpixel are red, blue, green and a fourth sub-pixel, where the fourthsub-pixel alternates between cyan and yellow.

The above aspects of embodiments of the invention demonstrated thealternating arrangement of pixels within each row in the case ofsingle-row pixels, or pair of rows in the case of double-row pixels. Insome embodiments of the invention, the arrangement of the rows or pixelswith respect to each other may further provide certain advantages.

With respect to single-row pixels, in some embodiments of the invention,the rows may be arranged in stripe fashion, such that each sub-pixel isvertically adjacent to sub-pixels of the same color. This may provideclean vertical lines and ease of manufacturing.

Reference is made to FIGS. 9A, 9B and 9C, which depict the single-rowpixel embodiment of the invention depicted in FIG. 6A, in whichsub-pixels in each row may be shifted versions of the arrangements inthe rows above them. Each row may be shifted by the same number ofsub-pixels. Thus, in FIG. 9A, each row is shifted by one sub-pixel. InFIG. 9B, each row is shifted by two sub-pixels. In FIG. 9C, each row isshifted by three sub-pixels. One advantage of shifted or staggeredarrangements is uniformity.

Reference is made to FIGS. 10A and 10B, which depict double-row pixelembodiments of the invention depicted in FIG. 8A, in which sub-pixels ineach pair of rows may be shifted versions of the arrangements in thepair of rows above them. Each pair of rows may be shifted by the samenumber of sub-pixels. Thus, in FIG. 10A, each pair of rows is shifted byone sub-pixel. In FIG. 10B, each pair of rows is shifted by twosub-pixels. A shift of any number of sub-pixels in either horizontaldirection may be possible, for example, one sub-pixel, two sub-pixels,three sub-pixels, etc.

Reference is made to FIGS. 11A and 11B, which depict the double-rowpixel arrangement of FIG. 8B. It will be recognized that in theembodiment of FIG. 11A, there is no shift between pairs of rows, becauseof the effective vertical shift between horizontally adjacent pixels.Thus, for example, a uniform distance is maintained between sub-pixelsof the same color. Other arrangements consistent with embodiments of thepresent invention are possible.

It will be noted that in some embodiments of the invention, such shiftedor staggered display sub-pixel arrangements may allow certain singlecolor sub-pixels to be placed more closely in the horizontal direction,thus improving resolution.

The above embodiments of the invention included non-white sub-pixels,e.g., red, blue, green, cyan and yellow sub-pixels. In some embodimentsof the invention, a display may include both white and non-whitesub-pixels. In some embodiments of the invention, each pixel may havefour sub-pixels, where each pixel includes red, green and bluesub-pixels, and the fourth color in each pixel alternates between yellowand white. This embodiment of the invention may produce yellowenhancement while providing enhanced brightness. It will be recognizedthat this embodiment of the invention may be used, for example, inconjunction with any of the above alternating cyan-yellow arrangementsby replacing cyan sub-pixels with white sub-pixels.

Although some of the exemplary devices, systems and/or methods describedabove are described in the context of devices for reproducing fiveprimary colors, it will be appreciated by those skilled in the art, thatsimilar devices, systems and/or methods may be implemented, withappropriate changes, in conjunction with devices for reproducing more orless than five primary colors.

While certain features of the invention have been illustrated anddescribed herein, many modifications, substitutions, changes, andequivalents will now occur to those of ordinary skill in the art. It is,therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the true spiritof the invention.

1. A display comprising a plurality of pixels, each pixel including atleast one constant-color sub-pixel having a color present in alladjacent pixels, and at least one alternating-color sub-pixel having acolor not present in at least one adjacent pixel, wherein the number ofnon-white colors of said constant-color and alternating-color sub-pixelsin the display is greater than three, wherein at least some pixels havea yellow alternating-color sub-pixel.
 2. The display of claim 1, whereinat least some pixels have a cyan alternating-color sub-pixel.
 3. Thedisplay of claim 2, wherein said yellow sub-pixel in a first pixel isadjacent to a cyan sub-pixel of a pixel adjacent to said first pixel. 4.The display of claim 1, wherein at least some pixels have a whitealternating-color sub-pixel.
 5. The display of claim 1, wherein saidpixels have a red constant-color sub-pixel.
 6. The display of claim 5,wherein said pixels have a green constant-color sub-pixel.
 7. Thedisplay of claim 6, wherein said pixels have a blue constant-colorsub-pixel.
 8. The display of claim 7, wherein in any pixel, red andgreen sub-pixels are adjacent to each other and blue and greensub-pixels are adjacent to each other.
 9. The display of claim 1,wherein each pixel comprises exactly four sub-pixels.
 10. The display ofclaim 1, wherein each pixel comprises exactly five sub-pixels.
 11. Thedisplay of claim 1, wherein each pixel comprises exactly six sub-pixels.12. The display of claim 1, wherein sub-pixels in each pixel arepositioned in a single horizontal row.
 13. The display of claim 12,wherein each sub-pixel is vertically adjacent to at least one sub-pixelof the same color.
 14. The display of claim 12, wherein the sub-pixelsin each row are horizontally shifted with respect tocorrespondingly-colored sub-pixels in a vertically adjacent row.
 15. Thedisplay of claim 1, wherein the sub-pixels in each pixel are positionedin two vertically adjacent horizontal rows.
 16. The display of claim 15,wherein each pixel consists of four sub-pixels.
 17. The display of claim16, wherein red, green and blue sub-pixels are located in the samerespective positions in each horizontally adjacent pixel.
 18. Thedisplay of claim 17, wherein red and green sub-pixels of each pixel areadjacent to each other and blue and green sub-pixels of each pixel areadjacent to each other.
 19. The display of claim 15, wherein thesub-pixels in each pair of rows are horizontally shifted with respect tocorresponding sub-pixels in a vertically adjacent pair of rows.
 20. Thedisplay of claim 19, wherein red and green sub-pixels of each pixel areadjacent to each other and blue and green sub-pixels of each pixel areadjacent to each other.
 21. In a display comprising a plurality ofpixels, each comprising a plurality of sub-pixels, whereinconstant-color sub-pixels are included in each pixel, andalternating-color sub-pixels are only included in less than all pixelsof the display, wherein the number n of non-white colors of saidconstant-color and alternating-color sub-pixels is greater than three, amethod of enhancing a displayed image with respect to an alternatingcolor comprising: obtaining a plurality of input pixel data pointscorresponding to a plurality of display locations at each display pixel;converting said plurality of input pixel data for each pixel inton-color data; and displaying on at least one constant-color sub-pixel ateach pixel an intensity value corresponding to the constant-colorintensity value of said converted pixel data modified based on anintensity value of said converted pixel data corresponding to analternating-color not present in said pixel.
 22. The method of claim 21,further comprising: displaying on a second constant-color sub-pixel ateach pixel an intensity value corresponding to the second constant-colorintensity value of said converted pixel data modified based on anintensity value of said converted pixel data corresponding to thealternating-color not present in said pixel.